1. Bordignon , M. Giarda , P. 2004 http://www.lavoce.info/
2. Department of Health 1997 http://webarchive.nationalarchives.gov.uk/20100407034821/ http://www.archive.official-documents.co.uk/document/doh/newnhs/forward.htm
3. Department of Health 2010 http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/@dh/@en/@ps/documents/digitalasset/dh_117794.pdf